Currently, with the enhancement in the quality of multimedia content, content including a multichannel audio signal having a relatively large number of channels compared to a 5.1-channel audio signal, such as a 7.1-channel audio signal, a 10.2-channel audio signal, a 13.2-channel audio signal, and a 22.2-channel audio signal is increasingly used. For example, there have been attempts to use a multichannel audio signal such as a 13.2-channel audio signal in the movie field and to use a multichannel audio signal such as a 10.2-channel audio signal and a 22.2-channel audio signal in a high quality broadcasting field such as an ultra high definition television (UHDTV).
However, user terminals of individual users may play back a stereotype audio signal such as a stereo speaker or a headphone. Accordingly, a high quality multichannel audio signal needs to be converted to a stereo audio signal that can be processed at a user terminal.
A down-mixing technology may be utilized for such a conversion process. Here, the down-mixing technology according to the related art generally down-mixes a 5.1-channel or 7.1 channel audio signal to a stereo audio signal. To this end, by making an audio signal pass a filter such as a head-related transfer function (HRTF) and a binaural room impulse response (BRIR) for each channel, a stereotype audio signal may be extracted.
However, the number of filters increases according to an increase in the number of channels and, in proportion thereto, a calculation amount also increases. In addition, there is a need to effectively apply a channel-by-channel feature of a multichannel audio signal.